Java Compiler command() Method

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Description

The Java Compiler command() method examines the argument type and its fields and perform some documented operation.

Note − This API is deprecated since Java 9 and is not available Java 21 onwards.

Declaration

Following is the declaration for java.lang.Compiler.command() method

public static boolean command(Object arg)

Parameters

Object arg − a compiler-specific argument

Return Value

This method returns a compiler-specific value, including null.

Exception

NullPointerException − if the compiler doesn't like a null arg.

Preparing a Command for a Compiler Example

The following example shows the usage of java.lang.Compiler.command() method. In this program, we've created two classes CompilerDemo and SubClass1. In main method, instances of CompilerDemo and SubClass1 are created. Using getClass() method, we've retrieved their classes. Now using command() method, we've compiled the CompilerDemo Class and result is printed.

package com.tutorialspoint;

public class CompilerDemo {

   public static void main(String[] args) {

      CompilerDemo cls = new CompilerDemo();
      CompilerDemo subcls = new SubClass1();

      // class CompilerDemo
      Class c = cls.getClass(); 
      System.out.println(c);

      // sub class SubClass1
      Class c1 = subcls.getClass();
      System.out.println(c1);

      /* Let's compile CompilerDemo class using command method */
      Object retval = Compiler.command("javac CompilerDemo");

      System.out.println("Return Value = " + retval); 
   }
} 

class SubClass1 extends CompilerDemo {
   // sub class
} 

Output

Let us compile and run the above program, this will produce the following result −

class com.tutorialspoint.CompilerDemo
class com.tutorialspoint.SubClass1
Return Value = null